2-Methyl-1-(4-methylphenyl)-3-piperidino-1-propanone (generic name: tolperisone) is known as one of .beta.-aminopropiophenone derivatives having a central muscle relaxant activity (G.B. 1,213,639). Tolperisone is widely used in Japan for the clinical treatment of spastic paralysis or motor palsy resulting from muscular hypertonia.
The potency and duration of tolperisone in its clinical use, however, are not always satisfactory, and the improvements thereof have been desired.